Divide fix ornl version (#39140)

* fix same unit on lhs and rhs but output not unitless

* only test it in divide

* release note

* delete .gitkeep

* better description

Author: KyleQianliMa

Framework/Algorithms/src/Divide.cpp

@@ -90,7 +90,7 @@ void Divide::setOutputUnits(const API::MatrixWorkspace_const_sptr lhs, const API
 
   // If the Y units match, then the output will be a distribution and will be
   // dimensionless
-  else if (lhs->YUnit() == rhs->YUnit() && m_rhsBlocksize > 1) {
+  else if (lhs->YUnit() == rhs->YUnit() && m_rhsBlocksize != 1) {
     out->setYUnit("");
     out->setDistribution(true);
   }

Framework/Algorithms/test/MultiplyDivideTest.in.h

@@ -1095,6 +1095,19 @@ class @MULTIPLYDIVIDETEST_CLASS@ : public CxxTest::TestSuite
     TS_ASSERT(result->YUnit().empty());
   }
 
+  void test_RaggedWorkspace_sameunit()
+  {
+    auto lhs = create_RaggedWorkspace();
+    auto rhs = create_RaggedWorkspace();
+    lhs->setYUnit("counts");
+    rhs->setYUnit("counts");
+    DO_DIVIDE = true;
+    auto result = performTest(lhs, rhs, false, DO_DIVIDE ? 1.0 : 4.0, DO_DIVIDE ? 1.4142135625 : 5.6568542436);
+    TS_ASSERT(result->isRaggedWorkspace());
+    TS_ASSERT_EQUALS(result->isDistribution(), DO_DIVIDE ? true : false);
+    TS_ASSERT(result->YUnit().empty());
+  }
+
   void test_RaggedWorkspace_and_single_value()
   {
     auto lhs = create_RaggedWorkspace();

docs/source/release/v6.13.0/Framework/Algorithms/Bugfixes/.gitkeep

@@ -0,0 +1 @@
+- Fixes a bug in  :ref:`algm-Divide` where units were not properly cleared when dividing two :ref:`ragged_workspace <Ragged_Workspace>` with identical Y-axis Units. This issue could cause errors in downstream data reduction workflows where the resulting workspace should be unitless. The fix ensures proper unit handling for :ref:`ragged_workspace <Ragged_Workspace>` division operations.